The invention relates to a sole for a ski, and in particular for a downhill ski.
Apart from a certain resistance to wear, the essential quality required for ski soles relates to their sliding capability.
The phenomena of sliding on snow or ice have been widely studied, and it emerges from these findings that sliding is principally inherent in the formation of a film of water below the sole, which facilitates and promotes the resulting sliding. This film of water is created as a result of the phenomena of friction of the sole on the snow or the ice, which give rise to a local temperature rise and consequently the melting of the snow or of the ice in this region.
The friction brought about by the sole is dependent on the one hand on the distribution of the weight of the skier in the region of the sole and on the other hand on the positioning of the ski in relation to the slope, according to whether the skier is in the course of turning or in a straight line, but is also dependent on the speed and in a general manner on the dynamics of the skier in the course of maneuvering in relation to the snow or the ice.
In fact, it has been possible to demonstrate that on the flat the distribution of pressure in the region of the ski takes place essentially in the region of the runner and, to a lesser degree, in the region of the lines of contact, front and rear respectively, of the ski. On the other hand, the pressure exerted is rather weak in the region of the other places of the sole.
This distribution of pressure is quite different as soon as the skier carries out turns. In fact, in such a case, it has been possible to show that in a turn the ski rested essentially on a fold of snow formed by the maneuvering of the ski, and this in the region of a very small portion of the surface of its sole and typically in the region of the lateral edge resting on the snow and that moreover this pressure was maximum in the region of the runner.
In fact, the pressure generated in the region of the runner is moreover accentuated by the dynamic effect which is added to the purely static effect inherent in the weight of the skier.